The present invention applies to a procedure for the decanting of dental filling substances from a storage container into individual containers consisting of a container body fitted with a jet at one end and an axially movable piston sealing the other end.
For use in dental practice, dental medical substances, e.g. photohardening filling substances, are packed in special individual containers that are often disposable. Such containers normally hold a quantity sufficient for one application of dental filling substance which the dentist needs to restore a prepared dental cavity.
Customary known procedures use an individual container without an integral piston, positioned in such a way that a hollow needle, protruding from the storage container for dental filling substances, reaches into the opening left by the removed piston in the individual container that has to be filled. By applying pressure, the dental filling substance is squeezed from the storage container through the hollow needle into the open individual container. In this process, the outlet of the hollow needle inside the individual container can be adjusted according to the rising level of dental filling substance in the individual container. With the decanting process completed, the individual container is sealed with the piston and a cap on the tip of the jet.
Decanting time depends on the quantity of the dental filling substance to be decanted but also on product properties, e.g. viscosity of the filling substance, and process parameters, e.g. the pressure applied while squeezing. In known decanting procedures the dental filling substance is squeezed through thin outlets that are shaped like hollow needles, from the storage container into the individual containers. Customary outlets feature a small diameter, causing decanting time to grow out of proportion with increasing viscosity of the dental filling substance, or requiring such a high pressure that detrimental effects may be suffered by the viscous filling substance. Owing to the severe strain on the outlet, this has to be made of metal for the most part or even completely. However, contact of abrasive filling substance with metal surfaces may lead to abraded particles from the outlet entering the filling substance decanted and thereby causing color changes. The practice of decanting procedures of the aforementioned kind is therefore lengthy and uneconomical especially for highly viscous, paste-like filling substances, and is fraught with disadvantages hitherto unavoidable.
An object of the invention, therefore, is to enable decanting of, dental filling substances of the aforementioned kind in a way such that highly viscous dental filling substances may also be decanted quickly and economically.
The above and other objects of the invention can be achieved by squeezing the dental filling substance through the jet into the container body while pushing the piston forward until it reaches a preset final position.
In order to perform the decanting process, the jet of the individual container is docked leakproof and pressure sealed to an outlet of the storage container. At the start of the decanting process the axially movable piston rests in the individual container close to the jet. Under pressure, dental filling substance is squeezed through the jet into the container body while pushing the piston forward ahead of it. The decanting process is finished as soon as the piston reaches a preset final position. Air trapped at the start of the decanting process in the individual container is released through the air relief profile of a piston sealing lip, which at the same time prevents an unintentional escape of dental filling substance through the individual container opening for the piston. In this way, the individual container is filled completely, and without residual air, with dental filling substance. This notably includes the jet, which, in known decanting procedures for highly viscous filling substances, is often filled only partially or not at all. As an additional advantage, filling substance exits immediately during dental treatment. So far, filling substance had to be squeezed through the initially empty jet by repeatedly actuating the applicator, before it would exit from the jet and be ready for application.
Preferably, the final position of the axially movable piston is adjustable. Via the adjustable final position of the piston, the available volume of the individual container for dental filling substance can be predetermined and the precise apportioning of the quantity decanted can be ascertained with utmost precision. In the event that a modification of the quantity of dental filling substance to be decanted should be desired, it can easily be obtained by modifying the final position of the piston.
According to a further embodiment of the invention, several individual containers can be filled simultaneously in a controlled manner through outlets in the storage container. The quantity of dental filling substance for the individual containers is determined by the correlated preset final position of the piston. No additional device is necessary for the apportioning of dental filling substance. Therefore, with comparatively little effort, many individual containers can be filled simultaneously in a precise and reproducible manner, signifying a substantial advantage concerning decanting performance and profitability.